The greatest problem with using a puncture-based weapon against zombies is that it may become lodged in the skull of your undead foe. That's a problem that Jörge Sprave, maker of the sawblade-firing slingshot, the pump-action slingshot, and the Gatling-gun slingshot has now solved. His weapon includes a standard slingshot on one end, and a mace on the other that's paired with a heavy spike. If your spike gets stuck in a skull, pull the lever to push it out.